﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication5
{
    class Program
    {
        static void Main(string[] args)
        {
            int result = 1;
            int number = Int32.Parse(Console.ReadLine());
            for (; number > 0; number--)
            {
                result = result * number;
            }

            Console.WriteLine(result);
            Console.ReadKey();







        }
    }
}
